Seroepidemiological studies of HIV-1 infection in large Brazilian cities.

The prevalence of HIV-1 infection in high risk populations in the high risk cities of Rio de Janeiro Sao Paulo and Santos Brazil is determined in this retrospective study. AIDs incidence coefficients are Sao Paulo (27.5/100000) Rio de Janeiro (14.1/100000) and Santos (45.4/100000). The 1st case was reported in 1982 and from 1982-1983 6202 cases have been reported (62% from Sao Paulo and 15.3% from Rio de Janeiro). 41.9% of AIDs cases are homosexual men and 19.5% are bisexual. Serum samples tested by indirect ELISA and confirmed with other methods were taken from hemophiliac patients Rio de Janeiro polytransfused hemodialysis patients from Sao Paulo intravenous drug addicts from Sao Paulo and Rio de Janeiro male prisoners from Sao Paulo and pregnant women from Santos. The results of hemophiliac patients for 1983/4 were that 98% were positive to antiHIV-1. In 1986 20% of the seropositive patients had developed AIDS (9 out of 10 died). The analysis of 1028 polytransfused hemodialysis patients between 1976-87 revealed positive antiHIV-1 results for 3% between 1985-6 and 7.7% (2 out of 14 died). There were also 6.3% false positives. Of the 18 drug addicts 15.9% were confirmed to be antiHIV-1 positive (1 had AIDs out of 30 seropositive). Of the 923 male prisoners 12.5% were antiHIV-1 positive. 3.6% of the pregnant women were confirmed to be antiHIV-1 positive. It is estimated that 2.5 million Brazilians have been infected with HIV-1 to date which if unchecked will parallel the situation in sub-Saharan Africa. The present laws allow for screening of the blood supply but clearly those hemophiliac patients treated before 1983 with factor VIII concentrates prepared with locally collected plasma are at high risk. The risk among polytransfused hemodialysis patients is much lower but still cause for concern. The heterosexual intravenous drug addicts attending clinics or throughout the population are at high risk even though there are no restrictions for buying syringes and needles in drugstores. The high prevalence in the prison population reflects homosexual or drug sharing exposure and are at high risk of spreading the infection through connubial visits. The pregnant women are at risk due to promiscuous sexual life and intravenous drug addiction but are a regional phenomena.